It is common practice in the taking of medical X-rays to place a pre-shaped lead marker on a portion of the patient's body to be examined. In common practice, for example, the lead marker “R” or “L” are used to distinguish the right from the left side of the body. Other markers serve to provide a visual reference point in the resultant X-ray film to facilitate interpretation of the X-ray. Once the preferred body structure has been determined on the film, its location can be ascertained relative to this lead marker.
It is also common practice in surgery (for cases in which fluoroscopic X-rays are utilized as a means of guiding the placement of instruments or implants during the procedure) to use a sterile surgical instrument by means holding it over a specific point on the patient's skin (after it has been prepped as a sterile field) while obtaining a fluoroscopic image. This enables the surgeon to plan the skin entry point of a percutaneous procedure. By acquiring the image with the tip of a superimposed surgical instrument held at the same locus on the patient's skin, an assessment of position relative to structures seen on the fluoroscopic image can be ascertained by the surgeon. If the first position selected by the surgeon is off the desired point on the fluoroscopic image, an adjustment is made by moving the instrument to a new locus and a second image is obtained. This procedure is repeated until the overlying instrument is at the correct spot on the skin corresponding to the appropriate locus on the fluoroscopic image. By moving the C-arm fluoroscope so that the direction of the beam is at 90 degrees to the initial one, an assessment of depth to the target locus can be made. This is the process that is utilized when finding the correct start point on the outer distal femur for interlocking nailing (with the modification of depth assessment where the second view is often obtained to verify screw length) and applies to circumstances where the instrument or implant is to be advanced “end on” the target tissue and parallel to the direction of the fluoroscopic or roentgenographic beam. In instances where this is not the case, e.g., when the start point for an intramedullary nailing on the skin needs to be determined, knowing that this position on the skin must be collinear with the proximal femoral shaft, the assessment of colinearity can be accomplished by applying the surgical targeting grid of the present invention so that it is collinear with the proximal femur on the lateral aspect (this may require C-arm fluoroscopic X-ray check during the act of grid placement, with extension of the placement cephalad as far as the buttock) as well placement of a second grid on the anterior aspect with extension cephalad as far as the buttock at which point it overlaps the first surgical targeting system. By noting which grid row overlies the proximal femoral canal on the anteroposterior projection and also noting which grid row from the second surgical targeting system overlies the proximal femoral canal on the lateral projection, the start point on the skin is given by the intersection of these two rows on the surface of the buttock area. This is of special importance in percutaneous intramedullary nailing procedures, where the selection of an incision point which is not collinear with the proximal femur may cause tenting of a large cuff of soft tissue during the procedure and may necessitate extension of a small incision. Finding this point on the skin might otherwise entail multiple fluoroscopic X-ray views, each of which impart radiation exposure to the patient as well as the surgeon and other operating room personnel. An additional point is that accurate location of this point permits a small skin incision and this, with healing becomes a small scar which, if later extraction of the device is opted for, facilitates the accomplishment of the procedure, again, as a percutaneous one (with a limited incision whose locus is given by the existing scar).
Another example of the utility of the system of the present invention provided by the procedure of reamed femoral intramedullary nailing. When the currently commonly utilized process (using an overlying radiopaque object to find a locus on the skin as described above) is used to monitor the passage of a surgical instrument down a surgical corridor, multiple additional fluoroscopic views may be needed. An example of this would be passage of a guidewire down an intramedullary canal for a fracture of the femur. Knowing which direction to point the angled tip of the guide wire entails knowing which direction the fragment on the other side of the fracture is displaced. Additional spot fluoroscopic views of the fracture with an overlying radiopaque object (such as a hemostat clamp, such as for clamping a blood vessel) gives the needed answer and prompts the surgeon to rotate the guidewire so that its tip is toward the intramedullary canal on the displaced fragment before advancing the wire down the fragment's canal. With a surgical targeting device of the present invention in place, obtaining additional fluoroscopic X-rays for this purpose are unnecessary. The added advantageous factor is that the surgeon need not place his hand near the radiation beam with the surgical instrument (this is an occupational hazzard for many surgeons). Additionally, minor directional adjustments in the passage of a radiopaque instrument or implant in the body can be subject to less guesswork because both the coordinates on the fluoroscopic screen and those directly readable on the patient can be correlated. “Guesswork” however may prompt the operator to take more fluoroscopic X-rays or may result in the need for several passes through the patient's tissues with the instrument or implant before the correct corridor is gotten. Having an in place targeting system of the present invention therefore, may provide the surgeon with a series of constant reference points throughout the entirety of the procedure. Having these may facilitate the accuracy and speed of the procedure and diminish the potential hazzard to the patient (additional radiation exposure and damage to tissues from inaccurate passage of instruments or implants under fluoroscopic control) as well as to the surgeon and the operating room personnel (radiation exposure).
U.S. Pat. No. 5,702,128 discloses a radiographic marker system and method of making it. The entire disclosure of U.S. Pat. No. 5,702,128 is hereby incorporated by reference herein. U.S. Pat. No. 5,052,035 (referred to herein as the “'035 patent”) discloses image location marking devices for radiographs, a method of marking and methods of use. The entire disclosure of U.S. Pat. No. 5,052,035 is hereby incorporated by reference herein.
Instead of a lead marker, the device disclosed in the '035 patent produces multiple parallel lines on an X-ray film bearing a radiographic image of a patient's body to facilitate the location of a part of the body or a retained foreign body or implant within that image. The device comprises a flexible substrate formed of a porous, translucent or transparent material having lines of a radiopaque material disposed thereon. The device is used by applying it over a selected portion of the patient's body to be X-rayed or scanned using computed tomography (CT). The resulting radiographic image of the selected portion of the person's body thus has indicator lines crossing it, which facilitates the demarcation of a desired portion of that image. A marking instrument, i.e., a marking pen, can be applied to the substrate at predetermined locations thereon while the device is on the person to mark the body at the selected location.
The device disclosed in the '035 patent is non-sterile and, therefore, can only be used in a non-sterile environment. Once the corresponding location has been marked on the patient's body, the device disclosed in the '035 patent is removed and discarded. The biopsy is then carried out normally using the mark placed on the skin as a reference point. If the surgeon would like to take another image with the device disclosed in the '035 patent in place, he would have to compromise the sterile field by replacing the device.
The Ioban® drape is a thin, flexible, adhesive sheet of plastic designed for use during a surgical procedure. The Ioban® drape is 100% impervious to liquid and bacteria, but permeable to oxygen and moisture vapor. Accordingly, a drape that is impervious to liquid strike through or fluid flow through it is an important feature of this device of the present invention. On the other hand, a drape that allows fluid transfer, and thus bacterial transfer, compromises the sterile field. This, in turn, potentially increases the risk of wound infection. For surgical procedures of length, active antimicrobial on the skin in the operative field is a desirable feature. Thus, the inclusion of an antiseptic coating on the drape of the present invention exposed to the skin provides an additional safeguard against infection.
Once a patient's skin has been prepped or prepared for surgery, the sterile Ioban® drape of the present invention is stretched over the area to be incised. The designed function of the Ioban® drape is to provide an added sterile and antiseptic protective barrier within the surgical field placed on the patient's skin and the adjacent operating environment. The Ioban® drape's adhesive properties are often used as a means of securing the sterile drapes or towels to the margins of the surgical field. This feature is an important one when the surgeon is planning a percutaneous procedure with fluoroscopic control, because securing the drapes and towels to the margins of the field in the customary fashion with the use of radiopaque towel clips might otherwise interfere with the ability of the operator to visualize the target or targeted area within the body on the fluoroscopic image.